diff --git a/ax_init_standard_project.m4 b/ax_init_standard_project.m4
index 157c37a..77c1e73 100644
--- a/ax_init_standard_project.m4
+++ b/ax_init_standard_project.m4
@@ -455,7 +455,7 @@ AC_DEFUN([AX_PKG_REQUIRE], [
       AC_MSG_ERROR([Required header $3 for feature $1 not found])
     ])
     CPPFLAGS=${old_CPPFLAGS}
-  else
+  elif test ${$1_found} -eq 0; then
     AC_MSG_ERROR([Required package $2 for feature $1 not installed])
   fi
 ])